None of the provisions of the Nebraska Indian Child Welfare Act, except subsection (1) of section 43-1504 and section 43-1511, shall affect a proceeding under state law for foster care placement, termination of parental rights, preadoptive placement, or adoptive placement which was initiated or completed prior to one hundred and eighty days after November 8, 1978, but shall apply to any subsequent proceeding in the same matter or subsequent proceedings affecting the custody or placement of the same child.